What is the Function of an Air Compressor?

by Herb Kirchhoff; Updated September 26, 2017
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An air compressor is a machine that uses an electric motor or gas engine to power a device that sucks in successive volumes of air from the atmosphere, compresses (squeezes) each volume of air in a confined place to increase its pressure by making the volume smaller, and then transfers the high-pressure air to a receiver tank, according to the EnergyTechPro educational website of DTE Energy. The high-pressure air is drawn off from the receiver tank to power equipment.

Three Basic Types

There are three basic types of air compressor, said EnergyTechPro. The first, called a reciprocating compressor, uses a piston in a cylinder to squeeze the air. The second, called a rotary screw compressor, uses a rotating spiral screw of gradually diminishing volume to compress the air. The third, called a centrifugal compressor, uses a rotating impeller to transfer momentum to the air, thereby compressing it.

Air System

The compressor is only one part of a complete air system, said the EnergyTechPro website. The receiver tank is a vital component that prevents unnecessary wear on the compressor from too-frequent cycling. The tank also eliminates pulsing of the air flow.

Purifiers and Coolers

An air system also includes purifiers that remove water vapor and compressor lubricant vapors from the compressed air as it is drawn off. There may also be coolers to reduce the temperature of the compressed air. Finally, there are the hoses or pipes that bring the high-pressure air to the locations where it will be put to work. The air available for work is measured in cubic feet per minute (cfm). The higher the cfm, the more power you have.

Wind in Reserve

Compressed air is a form of stored energy, in essence wind in reserve. It can do work when it expands back to atmospheric pressure as it is released, said EnergyTechPro. Among other things, compressed air is being used to power portable and stationary tools of many types, drive pneumatic motors that can replace internal combustion and electric motors, and run peak-load electric generating plants.

Compressor Markets

Reciprocating air compressors with motors of one to 50 horsepower are sold for home, small shop and light industrial uses where air demand is intermittent, said EnergyTechPro. Rotary compressors with motors exceeding 100 horsepower are sold for heavy industrial use where there’s a continuous demand for compressed air.

About the Author

Herb Kirchhoff has more than three decades of hands-on experience as an avid garden hobbyist and home handyman. Since retiring from the news business in 2008, Kirchhoff takes care of a 12-acre rural Michigan lakefront property and applies his experience to his vegetable and flower gardens and home repair and renovation projects.

Photo Credits

  • people at work, air compressor image by Greg Pickens from Fotolia.com